scsi: ufs: Add states to debug abnormal clocks turn off

On UFS based targets, sometimes we are seeing unclocked
access issues where UFS register is being accessed while
clocks are turned off. This change is to add states in
hold and release contexts which will help to debug such
issues further.

Change-Id: I255f3516471ed74b9d93320f5442adffaf312102
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>

drivers/scsi/ufs/ufshcd.c

@@ -1370,6 +1370,7 @@ start:
 	}
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 out:
+	hba->ufs_stats.clk_hold.ts = ktime_get();
 	return rc;
 }
 EXPORT_SYMBOL_GPL(ufshcd_hold);
@@ -1474,6 +1475,7 @@ static void __ufshcd_release(struct ufs_hba *hba, bool no_sched)
 
 	hba->clk_gating.state = REQ_CLKS_OFF;
 	trace_ufshcd_clk_gating(dev_name(hba->dev), hba->clk_gating.state);
+	hba->ufs_stats.clk_rel.ts = ktime_get();
 
 	hrtimer_start(&hba->clk_gating.gate_hrtimer,
 			ms_to_ktime(hba->clk_gating.delay_ms),
@@ -1920,8 +1922,10 @@ static void ufshcd_hibern8_exit_work(struct work_struct *work)
 
 	/* Exit from hibern8 */
 	if (ufshcd_is_link_hibern8(hba)) {
+		hba->ufs_stats.clk_hold.ctx = H8_EXIT_WORK;
 		ufshcd_hold(hba, false);
 		ret = ufshcd_uic_hibern8_exit(hba);
+		hba->ufs_stats.clk_rel.ctx = H8_EXIT_WORK;
 		ufshcd_release(hba, false);
 		if (!ret) {
 			spin_lock_irqsave(hba->host->host_lock, flags);
@@ -2344,6 +2348,7 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	int ret;
 	unsigned long flags;
 
+	hba->ufs_stats.clk_hold.ctx = UIC_CMD_SEND;
 	ufshcd_hold_all(hba);
 	mutex_lock(&hba->uic_cmd_mutex);
 	ufshcd_add_delay_before_dme_cmd(hba);
@@ -2357,6 +2362,7 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	ufshcd_save_tstamp_of_last_dme_cmd(hba);
 	mutex_unlock(&hba->uic_cmd_mutex);
 	ufshcd_release_all(hba);
+	hba->ufs_stats.clk_rel.ctx = UIC_CMD_SEND;
 
 	ufsdbg_error_inject_dispatcher(hba,
 		ERR_INJECT_UIC, 0, &ret);
@@ -2834,6 +2840,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 		goto out;
 	}
 
+	hba->ufs_stats.clk_hold.ctx = QUEUE_CMD;
 	err = ufshcd_hold(hba, true);
 	if (err) {
 		err = SCSI_MLQUEUE_HOST_BUSY;
@@ -2847,6 +2854,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	if (err) {
 		clear_bit_unlock(tag, &hba->lrb_in_use);
 		err = SCSI_MLQUEUE_HOST_BUSY;
+		hba->ufs_stats.clk_rel.ctx = QUEUE_CMD;
 		ufshcd_release(hba, true);
 		goto out;
 	}
@@ -4216,8 +4224,10 @@ static int ufshcd_uic_change_pwr_mode(struct ufs_hba *hba, u8 mode)
 	uic_cmd.command = UIC_CMD_DME_SET;
 	uic_cmd.argument1 = UIC_ARG_MIB(PA_PWRMODE);
 	uic_cmd.argument3 = mode;
+	hba->ufs_stats.clk_hold.ctx = PWRCTL_CMD_SEND;
 	ufshcd_hold_all(hba);
 	ret = ufshcd_uic_pwr_ctrl(hba, &uic_cmd);
+	hba->ufs_stats.clk_rel.ctx = PWRCTL_CMD_SEND;
 	ufshcd_release_all(hba);
 out:
 	return ret;
@@ -5385,6 +5395,7 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
 			update_req_stats(hba, lrbp);
 			/* Mark completed command as NULL in LRB */
 			lrbp->cmd = NULL;
+			hba->ufs_stats.clk_rel.ctx = XFR_REQ_COMPL;
 			__ufshcd_release(hba, false);
 			__ufshcd_hibern8_release(hba, false);
 			if (cmd->request) {
@@ -5907,6 +5918,7 @@ static void ufshcd_err_handler(struct work_struct *work)
 	if (unlikely((hba->clk_gating.state != CLKS_ON) &&
 	    ufshcd_is_auto_hibern8_supported(hba))) {
 		spin_unlock_irqrestore(hba->host->host_lock, flags);
+		hba->ufs_stats.clk_hold.ctx = ERR_HNDLR_WORK;
 		ufshcd_hold(hba, false);
 		spin_lock_irqsave(hba->host->host_lock, flags);
 		clks_enabled = true;
@@ -6049,8 +6061,10 @@ skip_err_handling:
 
 	hba->silence_err_logs = false;
 
-	if (clks_enabled)
+	if (clks_enabled) {
 		__ufshcd_release(hba, false);
+		hba->ufs_stats.clk_rel.ctx = ERR_HNDLR_WORK;
+	}
 out:
 	ufshcd_clear_eh_in_progress(hba);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
@@ -6286,7 +6300,8 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)
 
 	spin_lock(hba->host->host_lock);
 	intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
-
+	hba->ufs_stats.last_intr_status = intr_status;
+	hba->ufs_stats.last_intr_ts = ktime_get();
 	/*
 	 * There could be max of hba->nutrs reqs in flight and in worst case
 	 * if the reqs get finished 1 by 1 after the interrupt status is
@@ -6365,6 +6380,7 @@ static int ufshcd_issue_tm_cmd(struct ufs_hba *hba, int lun_id, int task_id,
 	 * the maximum wait time is bounded by %TM_CMD_TIMEOUT.
 	 */
 	wait_event(hba->tm_tag_wq, ufshcd_get_tm_free_slot(hba, &free_slot));
+	hba->ufs_stats.clk_hold.ctx = TM_CMD_SEND;
 	ufshcd_hold_all(hba);
 
 	spin_lock_irqsave(host->host_lock, flags);
@@ -6422,6 +6438,7 @@ static int ufshcd_issue_tm_cmd(struct ufs_hba *hba, int lun_id, int task_id,
 	clear_bit(free_slot, &hba->tm_condition);
 	ufshcd_put_tm_slot(hba, free_slot);
 	wake_up(&hba->tm_tag_wq);
+	hba->ufs_stats.clk_rel.ctx = TM_CMD_SEND;
 
 	ufshcd_release_all(hba);
 	return err;
@@ -9315,6 +9332,7 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
 	int ret = 0;
 
 	/* let's not get into low power until clock scaling is completed */
+	hba->ufs_stats.clk_hold.ctx = CLK_SCALE_WORK;
 	ufshcd_hold_all(hba);
 
 	ret = ufshcd_clock_scaling_prepare(hba);
@@ -9378,6 +9396,7 @@ scale_up_gear:
 clk_scaling_unprepare:
 	ufshcd_clock_scaling_unprepare(hba);
 out:
+	hba->ufs_stats.clk_rel.ctx = CLK_SCALE_WORK;
 	ufshcd_release_all(hba);
 	return ret;
 }

drivers/scsi/ufs/ufshcd.h

@@ -3,7 +3,7 @@
  *
  * This code is based on drivers/scsi/ufs/ufshcd.h
  * Copyright (C) 2011-2013 Samsung India Software Operations
- * Copyright (c) 2013-2016, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
  *
  * Authors:
  *	Santosh Yaraganavi <santosh.sy@samsung.com>
@@ -588,6 +588,22 @@ struct ufshcd_req_stat {
 };
 #endif
 
+enum ufshcd_ctx {
+	QUEUE_CMD,
+	ERR_HNDLR_WORK,
+	H8_EXIT_WORK,
+	UIC_CMD_SEND,
+	PWRCTL_CMD_SEND,
+	TM_CMD_SEND,
+	XFR_REQ_COMPL,
+	CLK_SCALE_WORK,
+};
+
+struct ufshcd_clk_ctx {
+	ktime_t ts;
+	enum ufshcd_ctx ctx;
+};
+
 /**
  * struct ufs_stats - keeps usage/err statistics
  * @enabled: enable tag stats for debugfs
@@ -616,6 +632,10 @@ struct ufs_stats {
 	int query_stats_arr[UPIU_QUERY_OPCODE_MAX][MAX_QUERY_IDN];
 
 #endif
+	u32 last_intr_status;
+	ktime_t last_intr_ts;
+	struct ufshcd_clk_ctx clk_hold;
+	struct ufshcd_clk_ctx clk_rel;
 	u32 hibern8_exit_cnt;
 	ktime_t last_hibern8_exit_tstamp;
 	struct ufs_uic_err_reg_hist pa_err;